The present invention relates to a composite polymeric material having high resistance to impact energy.
Specifically, the present invention relates to a composite polymeric material, to the corresponding preparation process and to manufactured articles having high impact energy absorption.
Currently, manufactured articles for automotive parts capable of absorbing impact energy, such as structures for vehicle interiors and exteriors, motorcycle crash helmets and others, are made of a single material having a polymeric base, such as expanded polystyrene, expanded polypropylene, or polyurethane foams.
These manufactured articles are generally produced with a molding technology which entails injecting an expandable polymer into a mold having a preset shape and then expanding the polymer in the presence of catalysts and/or expansion agents. At the end of the expansion, the polymer hardens and acquires the preset shape of the mold.
In particular, in the production of polyurethane manufactured articles, polyisocyanates and polyesters or glycols are injected into the mold and are made to polymerize in the presence of catalysts and expansion agents. During polymerization, the polyurethane foam forms and, by expanding, takes the shape of the mold.
However, manufactured articles resistant to impact energy made of a single polymeric material produced according to conventional technology are not free from having drawbacks in use, mainly due to the fact that they are made of a single polymeric material which does not provide an adequate resistance response to the impact and to the shock wave. In particular, the only variable that is available to the designer is the density of the material.
For example, impact-resistant manufactured articles made of a single polymer according to the prior art, particularly expanded polystyrene helmets for motorcycles, have the drawback that they lose their impact-resistance characteristics after a single impact that causes a permanent deformation of the structure.
In the case of fenders for cars or of motorcycle helmets, permanent deformation after an impact accordingly compromises their safety characteristics, forcing the user to replace the manufactured article.